# Operations

Blockchain state can be accessed using state access operations. There are two types of operations, *read operation* and *write operation*, and they are again classified into two categories: *simple operation* and *composite operation*. Simple operations are those that have only one access reference point (i.e., data path in the blockchain database), while composite operations have multiple access reference points.

## Read Operations

There is no permission required for read operations.

### Simple Operations

| Target   | Operator      | Parameters                     | Action                                               |
| -------- | ------------- | ------------------------------ | ---------------------------------------------------- |
| value    | GET\_VALUE    | ref                            | Get the value on the path reference                  |
| rule     | GET\_RULE     | ref                            | Get the rule config on the path reference            |
| owner    | GET\_OWNER    | ref                            | Get the owner config on the path reference           |
| function | GET\_FUNCTION | ref                            | Get a triggering function hash on the path reference |
| rule     | EVAL\_RULE    | ref, address, value, timestamp | Evaluate the rule config on the path reference       |
| owner    | EVAL\_OWNER   | ref, address                   | Evaluate the owner config on the path reference      |

### Composite Operations

| Target                          | Operator | Parameters                        | Action                                                                 | Rule requirements |
| ------------------------------- | -------- | --------------------------------- | ---------------------------------------------------------------------- | ----------------- |
| value, rule, owner, or function | GET      | op\_list (list of get operations) | Get multiple path-value, path-rule, path-owner, or path-function pairs | None              |

## Write Operations

Each write operation has permission requirements depending on its type and path reference.

### Simple Operations

| Target   | Operator      | Parameters    | Action                                             | Required Permission                   |
| -------- | ------------- | ------------- | -------------------------------------------------- | ------------------------------------- |
| value    | SET\_VALUE    | ref, value    | Set the value on the path reference                | Value write permission on the path    |
| value    | INC\_VALUE    | ref, value    | Increment the value on the path reference by delta | Value write permission on the path    |
| value    | DEC\_VALUE    | ref, value    | Decrement the value on the path reference by delta | Value write permission on the path    |
| rule     | SET\_RULE     | ref, rule     | Set the rule on the path reference                 | Rule write permission on the path     |
| owner    | SET\_OWNER    | ref, owner    | Set the owner on the path reference                | Owner write permission on the path    |
| function | SET\_FUNCTION | ref, funcHash | Set a triggering function on the path reference    | Function write permission on the path |

### Composite Operations

There are two composite write operations, SET and BATCH:

| Target                          | Operator | Parameters                          | Action                                                                 | Rule requirements                                 |
| ------------------------------- | -------- | ----------------------------------- | ---------------------------------------------------------------------- | ------------------------------------------------- |
| value, rule, owner, or function | SET      | op\_list (an array of operations)   | Set multiple path-value, path-rule, path-owner, or path-function pairs | Write permission on **all** the paths             |
| value, rule, owner, or function | BATCH    | tx\_list (an array of transactions) | Handle each transaction independently                                  | Write permission on the paths of each transaction |

The SET and BATCH operations can be compared as follows:

| Comparison | SET Operation                                                       | BATCH Operation                                                                                                              |
| ---------- | ------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| structure  | Has multiple operations in op\_list                                 | Has multiple transactions in tx\_list                                                                                        |
| atomicity  | The whole operation fails if one of the operation in op\_list fails | The transactions in tx\_list are executed independently, i.e., failure of one transaction does not affect other transactions |
| order      | Broadcasted in a bundle and executed in the given order             | Broadcasted in a bundle and executed in the given order                                                                      |